The present invention relates to microelectromechanical systems devices having a thermally isolated membrane.
Microelectromechanical systems devices, or MEMS devices, generally include a combination of electrical and mechanical components. MEMS devices are often designed to function as sensors, actuators, conductors, or the like located in various application areas including the computer industry, automotive industry, and biomedical industry. The MEMS device may be employed to sense, measure, and control different characteristics or properties of the application in which the device is being used.
A MEMS device for thermal applications typically includes a semiconductor substrate and a membrane or diaphragm mounted on the semiconductor substrate. The membrane acts as a support structure for functional components (electrical, mechanical, thermal, etc.), which are disposed on the membrane. The membrane is formed from insulating materials that are designed to minimize thermal transfer from the functional components to the semiconductor substrate. The functional components are commonly encased in a protective film to prevent damage to the functional components during use of the device. A cavity may be formed in the semiconductor substrate beneath the portion of the membrane that supports the functional components. This cavity further prevents thermal transfer from the functional components.
However, because that portion of the membrane extending over the cavity is not mechanically supported, the membrane may be mechanically weak and susceptible to breakage during processing, packaging, or during use of the MEMS device in the various application areas.